Amazon Bedrock AgentCore

Amazon Bedrock AgentCore replaced Bedrock Agents Classic (closed to new customers July 30, 2026) with a fundamentally different architecture. Where the original Bedrock Agents was a single-agent framework with basic tool calling, AgentCore is built around composable services that teams can use together or independently: a runtime with session isolation and microVM sandboxes, a gateway that converts existing APIs and Lambda functions into MCP-compatible agent tools, identity management with authentication delegation, policy enforcement using natural-language rules that compile to Cedar (AWS's open-source policy language), and observability with built-in evaluations.

The managed harness is one of its most talked-about features. Developers declare a model, a system prompt, and a set of tools, and AgentCore runs the full agent loop including reasoning, tool selection, execution, and response streaming, with no orchestration code to write. Sessions get their own isolated filesystem so agents can suspend mid-task and resume exactly where they left off. The harness is model-agnostic, meaning you can swap models mid-session or override configuration per invocation without redeployment.

AgentCore also includes a payments module (in preview, built with Coinbase and Stripe) that lets agents autonomously pay for APIs and services using the x402 protocol, a spending-limit enforcement system at the infrastructure layer. For teams already on AWS, AgentCore is one of the most complete end-to-end stacks for going from agent prototype to production without managing containers or writing custom orchestration infrastructure.